Enzymic procedural steps are also increasingly being used in industrial processes for preparing organic compounds. This is due, inter alia, to the fact that the enzymes which are employed as biocatalysts already display an appropriate industrial effect in small quantities, the catalysis can in principle take place under mild reaction conditions (temperature, pressure and pH) and, at the same time, the enzymic transformation is associated with a high degree of enantioselectivity, regioselectivity or chemoselectivity. For this reason, efforts are still being made to improve these conversion reactions, and make them utilizable in an industrial process, with a view to exploiting these advantages in as broad a context as possible.
In this connection, the possibility of industrially preparing organic compounds by way of asymmetric enzymic transformations is being investigated in detail. In this context, it can frequently be found that disadvantages emerge with regard to using enzymes in large industrial dimensions, which disadvantages, such as excessive solvent use and solubility or material transport problems, call into question the use of the enzymes for these purposes. In this connection, the implementation of biocatalytic reactions using high substrate concentrations is particularly challenging.
Landfester et al. describe the enzymic polymerization of lactones in systems which exhibit a continuous aqueous phase in which a discontinuous hydrophobic phase is distributed in what are termed miniemulsion droplets. This miniemulsion is obtained, inter alia, by the action of ultrasound or high pressure homogenizers on a mixture which possesses these two phases. In addition, hydrophobic auxiliary substances and surfactants are present in the mixture for the purpose of stabilizing the droplets (Macromol. Rapid Commun. 2003, 24, 512-516; DE10248455).